80 lines
2.7 KiB
C++
80 lines
2.7 KiB
C++
// Copyright (c) 2013, Facebook, Inc. All rights reserved.
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// This source code is licensed under both the GPLv2 (found in the
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// COPYING file in the root directory) and Apache 2.0 License
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// (found in the LICENSE.Apache file in the root directory).
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//
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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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#pragma once
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#include "util/histogram.h"
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#include "rocksdb/env.h"
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namespace rocksdb {
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class HistogramWindowingImpl : public Histogram
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{
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public:
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HistogramWindowingImpl();
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HistogramWindowingImpl(uint64_t num_windows,
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uint64_t micros_per_window,
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uint64_t min_num_per_window);
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HistogramWindowingImpl(const HistogramImpl&) = delete;
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HistogramWindowingImpl& operator=(const HistogramImpl&) = delete;
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~HistogramWindowingImpl();
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virtual void Clear() override;
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virtual bool Empty() const override;
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virtual void Add(uint64_t value) override;
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virtual void Merge(const Histogram& other) override;
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void Merge(const HistogramWindowingImpl& other);
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virtual std::string ToString() const override;
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virtual const char* Name() const override { return "HistogramWindowingImpl"; }
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virtual uint64_t min() const override { return stats_.min(); }
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virtual uint64_t max() const override { return stats_.max(); }
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virtual uint64_t num() const override { return stats_.num(); }
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virtual double Median() const override;
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virtual double Percentile(double p) const override;
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virtual double Average() const override;
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virtual double StandardDeviation() const override;
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virtual void Data(HistogramData* const data) const override;
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private:
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void TimerTick();
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void SwapHistoryBucket();
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inline uint64_t current_window() const {
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return current_window_.load(std::memory_order_relaxed);
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}
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inline uint64_t last_swap_time() const{
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return last_swap_time_.load(std::memory_order_relaxed);
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}
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Env* env_;
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std::mutex mutex_;
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// Aggregated stats over windows_stats_, all the computation is done
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// upon aggregated values
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HistogramStat stats_;
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// This is a circular array representing the latest N time-windows.
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// Each entry stores a time-window of data. Expiration is done
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// on window-based.
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std::unique_ptr<HistogramStat[]> window_stats_;
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std::atomic_uint_fast64_t current_window_;
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std::atomic_uint_fast64_t last_swap_time_;
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// Following parameters are configuable
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uint64_t num_windows_ = 5;
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uint64_t micros_per_window_ = 60000000;
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// By default, don't care about the number of values in current window
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// when decide whether to swap windows or not.
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uint64_t min_num_per_window_ = 0;
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};
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} // namespace rocksdb
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